Apparatus for acquiring and laying real time 3-d information

ABSTRACT

Apparatus for producing energy pulses of a sufficiently short duration that only a restricted zone of the target image is illuminated at any given instant. A gating apparatus is adapted to admit to a receiving apparatus a sequence of images from the target subject, each of which images corresponds to a different zone of the target subject. The receiving apparatus is coupled to a recording device that presents to the viewer a threedimensional image of the target subject and that stores the image data for subsequent presentation. Several variations of the three-dimensional data acquisition and display devices are disclosed.

Unite States atet 1151 3,682,553

Kapany, Narinder S. [45] Aug. 8, 1972 3,428,393 2/1969 Montebello..352/43 3,448,208 6/1969 Chisnell etal ..l78/6.5 I t i: N d S w dFOREIGN PATENTS OR APPLICATIONS nven I j er e 144,715 3/1949 Austraha..343/112 R Assigneei p l gy, P310 Alto Primary Examiner-Rodney D.Bennett, Jr.

callf- Assistant Examiner--S. c. Buczinski [22] Fil d; Sept 19, 9 3Attorney-Townsend and Townsend [2i] Appl. No.: 760,896 Apparatus forproducing energy pulses of a suffi- [52] f 1 ciently short duration thatonly a restricted zone of the A 51 Im. c1. ..G0lc 3/08 target magenummated at any gm ing apparatus is adapted to admit to a receiving ap-[58] Flew of 1 3 1 3 paratus a sequence of images from the targetsubject, l l each of which images corresponds to a different zone of thetarget subject. The receiving apparatus is cou- [56] References C'tedpled to a recording device that presents to the viewer UNITED STATESPATENTS a three-dimensional image of the target subject and that storesthe image data for subsequent presentation. g fil Several variations ofthe three-dimensional data 6 lg t l d di 1 d 3,194,108 7/1965 Gunther..356/6 acquls an Sp ay evlces are c 056 3,246,330 4/ 1966 Balding..343/7 7 Claims, 8 Drawing Figures PULSER 24 RANGE GATE 22 GENERATOR 3SHUTTERING 21 L20 DEVICE PATENT'Emuc 8 I972 3.682.553

sum 1 or 3 I N VEN TOR.

wuSmQ NARINDER S. KAPANY BY f M :MM

ATTORNEYS mwmmouwm moEwmzwo mEo moz/ uz w mmm sm PATENTEDAUM 19123.882553 sum 2 or 3 INVENTOR. NARINDER S. KAPANY I ATTORNEYS fmmwLM W IPATENTEDAUG 8 I972 SHEET 3 0F 3 FIG.7

I NVENTOR.

NARINDER S. KAPANY FIG. 8

112 7m M1 final/1f ATTORNEYS APPARATUS FOR ACQUIRING AND LAYING REAL 3-DINFORMATION This invention relates to apparatus for acquiring anddisplaying information regarding the shape and depth of a targetsubject. The invention affords acquisition and display of information insuch manner that, to the viewer of the display system constituting partof the invention, the three-dimensional (3-D) character of the targetsubject is preserved.

An image of a solid target subject, i.e., a subject hav ing depth, canbe considered to be a composite of images of discrete juxtaposed zones,each of which zones is spaced a different distance from the viewer. Inmathematic terminology, if the viewer is assumed to be positioned at theorigin of a system of Cartesian coordinates, each such zone has specificX and Y characteristics within the bounds of different and discrete Zplanes. The present invention provides for the sequential illuminationof each zone by an energy source that can be pulsed to produce pulsesthat are extremely short with respect to the speed of propagation of theilluminating energy in the atmosphere or medium in which the targetsubject resides. For example, light travels through air at a rate 3 Xmeters per second; a pulse of light of l X 10' second duration isattainable by state-of-the-art techniques and will illuminate, at agiven instant, a zone on the target subject that has a Z dimension of0.3 meter, or about I foot. The present invention also providesapparatus for identifying each such zone as it is illuminated so that aplurality of images of such zones can be combined to produce a compositeimage. Finally, the present invention provides a display device forcreating an accurate 3-D display of the composite image of the targetsubject.

Information necessary for production of a 3-D presentation is acquiredinthe form of a sequence of image frames that are spaced apart from oneanother in the time domain. In the first instance, the individual framesare acquired by illuminating the object with a very short durationenergy pulse, and by providing a viewing or receiving device that can bepulsed on and off by an equally short pulse. The shortness of the pulsedetermines the depth resolution of the system, a light pulse of onenanosecond duration providing a depth resolution in the atmosphere ofapproximately 1 foot, and a pulse width of one picosecond durationproviding a system with a depth resolution in the atmosphere ofapproximately 0.01 inch. The time duration of each individual image issufiiciently short that plural images can be combined to create acomposite image that is free of flicker.

An object of this invention is to provide apparatus for acquiring aclear image of a target subject irrespective of the presence ofinterfering matter, such as fog or dust, between the apparatus and thetarget subject. In atmospheres containing fog or dust, backscatter oflight from the fog or dust, as well as the opacity of the fog or dust,obscures the target from clear view because such backscatter dazzles theviewer. The stated object is achieved according to the present inventionby acquiring images of only those Z planes that contain the .tar-

get subject but rejecting images of those Z planes that contain nothingbut dazzling backscatter from the fog or dust.

Another object is to provide an apparatus and a method in which the Zdistances between the various images acquired can be varied or adjustedto introduce nonlinearities, thereby to eliminate or ameliorate depthdistortion, or to emphasize or magnify one specific Z region of thetarget subject. According to the present invention, the distancesbetween the images of adjacent Z planes are proportional to the timeintervals between the formation of the respective images. Such timeintervals can be varied and controlled simply and accurate- 1y, as aconsequence of which distortion elimination or selective minification ormagnification can be accurately and simply effected.

The above stated object is advantageously employed to compensate fordepth distortions arising from the fact that the degree of magnificationin an optical system bears an inverse square law relationship todistance. Without compensation, near zones of a target subject aremagnified by a greater degree than are remote zones of the targetsubject. This phenomenon is particularly noticeable when the targetsubject is very near the optical system. The present invention afiordsamelioration of this problem because it develops a unique image for eachZ plane and such images corresponding to near zones of a target subjectare magnified to a lesser degree than images corresponding to remote Zplane zones of the same target.

Still another object of the present invention is the provision of adisplay device that presents to the viewer an image of the target thatappears in a truly threedimensional aspect. The display device presentsimages of zones of a target subject at different real distances or atdifferent apparent distances from the viewers eyes, thereby achievingthe 3-D effect.

Yet another object of the present invention is to provide a displayapparatus capable of displaying, in 3-D form, images of either apreviously acquired real target subject or a subject that has beencalculated from analytical or abstract computer-generated data. Thisobject can be achieved because the apparatus of this invention iscapable of presenting to the viewer for simultaneous viewing images ofplural Z planes of the target subject. Because the apparatus is capableof integrating plural images, it is useful for displaying stored data,such as data from a magnetic tape or like memory device.

A further object of the present invention is to provide a system thatcan be adapted for image acquisition in substantially any medium bychanging the frequency of the energy pulses employed. Thus in theatmosphere energy sources in the radar or visible bands of the spectrumcan be employed to advantage, and in a medium such as water the sonic oraudio bands of the spectrum can be used to advantage.

Other objects, features and advantages of the present invention will bemore apparent after referring to the following specification andaccompanying drawings in which:

FIG. 1 is a diagrammatic view of a system according to the presentinvention;

FIG. 2 is a timing diagram showing the time relationship of variouspulses employed during operation of the system of FIG. 1;

FIG. 3 is a perspective view of one form of mechanical display deviceaccording to the present invention;

FIG. 4 is a modification of a portion of the apparatus of FIG. 3;

FIG. 5 is a view of another modification of a portion of the apparatusof FIG. 3;

FIG. 6 is a perspective view of still another form of a 3-D viewer ofthe invention;

FIG. 7 is a view of yet another form of the 3-D viewer; and

FIG. 8 is a view of still another form of viewer.

Referring more particularly to the drawings, reference numeral 12indicates a source of wave energy such as a laser, the output of whichis aimed by an optical system 14 at a target subject 0. An opticalsystem 16 is fixed with respect to optical system 14 so as to be adaptedto receive energy from source 12 that is reflected by target subject 0.Such energy is imaged by the optical system onto a shuttering device 18,which device, when opened, admits the image to a recording device 20.

In the context of the present patent application, it is to be understoodthat recorder 20 can be any device that records, whether momentarily orpermanently, the image gated to it through shuttering device 18. Thus,according to the broad meaning intended to be given to the elementdescribed and claimed as recorder herein, such recorder can be a lenssystem for instantaneously transferring the image from shuttering device18 to a display device 21 or it can be a storage or recording devicesuch as magnetic core, magnetic tape, or the like.

A range gate generator circuit 22 is operatively connected to shutteringdevice 18 to control the time and duration that the shuttering device isopened. In the preferred form of the present invention, the gategenerator circuit 22 is adapted to open shuttering device 18 for aduration that is short with respect to the time required for an energypulse from source 12 to advance a given distance along target subject 0.The shorter the duration of opening shutter device 18, the higher thedegree of resolution achievable by the apparatus of the invention.

Energy source 12 is periodically activated by a pulser circuit 24; atrigger signal is produced by pulser 24 and is connected to a gategenerator circuit 22. Gate generator circuit 22 is adapted to generategate pulses at predetermined delay intervals after each pulse frompulser 24 so that a different segment of target subject 0 will betransferred into recording apparatus 20 for each complete signalgenerated by generator circuit 22.

In one system designed according to the present invention, opticalsystem 14 is designed to constrain the output of energy source 12 to anangle approximately 20 X radians, which at l kilometer produces an imageinto optical system 16 that encompasses an angle of 0.3 X 10' radians.With such system it is possible to detect l0 elements of information ineach of the horizontal and vertical directions. Such system operates atan average laser power of 1 watt, a peak laser power of 10 watts, and anenergy per pulse of 10- joule.

A full equivalent to the structure and mode of operation described aboveis opening and closing of shuttering device 18 a plurality of times inrapid succession for a single pulse from energy source 12. Each occasionthat the shuttering device is open effects transference of a discrete Zplane image to recording apparatus 20.

In order to achieve an appropriate gate signal from gate generatorcircuit 22, the generator is arranged to produce a gating signal at atime that is delayed by a variable amount from the time of the pulsefrom pulser 24. State-of-the-art techniques for achieving such delay ina programmable manner include: optical, distributed constant variabledelay line, dual sawtooth electronic delay, and tapped delay line gatedsequentially.

With reference to FIG. 2, the output of pulser 24 is indicated byunifomily repetitive pulses 26. The first of a sequence of gate pulsesis a pulse 28a, which is generated at a time T after generation of thepulse from pulser 24 which initiates the energy pulsed from energysource 12. The opening of shuttering device 18 by gate pulse 28a occursat a time when segment a (see FIG. 1) of target subject 0 has beenilluminated by energy source 12. Accordingly, the image formed byoptical system 16 onto recording device 20 corresponds to segment a,such image being indicated at 300 in FIG. 2.

The succeeding pulse from energy source 12 occurs at a time indicated at26b in FIG. 2. When the energy source 12 is activated by pulse 26b, gategenerator circuit 22 is correspondingly activated, and at an interval oftime later, namely T+t, a gate signal 28b is generated. Gate signal 28boccurs at a time with respect to pulse 26b that is t units of time laterthan the interval between pulses 28a and 26a. Gate pulse 28b opensshuttering device 18 to effect formation of an image on recording device20 that is shown at 3012 and indicated diagrammatically at b in FIG. 1.

The next succeeding pulse produced by pulser 24 is designated as 260 inFIG. 2. When such pulse occurs, energy source 12 is activated andtransmits a pulse of wave energy toward target subject 0. At a timeequal to T+2t after the occurrence of pulse 266, gate circuit 22produces a gate pulse 280. Such pulse gates through to the recordingdevice 20 an image schematically depicted at 300 in FIG. 2 and indicatedon target subject 0 in FIG. 1 as c. Subsequently, a pulse 26d occurs andinitiates generation of a gate pulse 28d which occurs T+3t units of timeafter pulse 26d. Consequently, segment d of target subject 0 is imagedonto recording device 20, the image resembling the schematicrepresentation at 30d in FIG. 2. Subsequent pulses 26 from pulser 24occur to generate a sequence of gate pulses up to 28' (the nth discretegate pulse) which is delayed from the pulse 26 that initiates it by T+ntunits of time. It will be seen that the present system produces ndiscrete images corresponding to different portions of target subject 0and each of the images corresponds to a different depth dimension oftarget subject 0. Also included as an element in the present inventionis a device 21 for displaying the images in such way as to produce tothe user of the apparatus a real time 3-D view.

Referring to FIG. 3, a 3-D display device 21 is coupled to shutteringdevice 18 (not shown in FIG. 3) via a fiber-optic bundle 32. The outletend of the bundle is fixed at 34 in confronting relation to the rearface of a disk 36, a lens system schematically indicated at 38 beinginterposed between the fiber-optic bundle and the disk to form an imageon the disk. Disk 36 is secured to the shaft 40 of a motor 42, whichmotor is energized so as to rotate disk 36 when 3-D viewing is takingplace. Opposite the front face of disk 36 is a viewing station 44 inalignment with lens 38 and with a segment of disk 36 adjacent to andinward of the outer periphery.

Disk 36 has mounted around the periphery thereof, at equally, radiallyand circumferentially spaced intervals, a plurality of fiber-opticbodies 48. The rear faces of the respective fiber-optic bodies aredisposed in mutually coplanar relationship, The front faces of thefiber-optic bodies, however, are spaced from viewing station 44 bydifferent amounts since the fiber-optic bodies have difierent lengths.According y, a fiberoptic body 48a will produce an image that appearscloser to a viewer at station 44 than will a fiber-optic body 48b whichis slightly shorter than the former fiberoptic body. Fiber-optic body48c is in turn shorter than fiber-optic body 48b and fiber-optic body48d is shorter than fiber-optic body 480. Consequently, by synchronizingthe rotation of wheel 36 with the gating of the images 30 (FIG. 2), areal time 3-D view of target subject 0 is afforded a viewer peering intothe apparatus from viewing station 44.

The synchronization is achieved in part by providing a link betweenviewing device 21 and the gate generator circuit 22, such link beingdesignated schematically in FIG. 1 at 50. A suitable synchronizing linkis constituted by an electromagnetic pickup head 52 disposed adjacentthe periphery of disk 36 and an iron slug 54 located in the periphery ofthe disk to induce in the pickup head 52 an electric signal each timedisk 36 makes one revolution.

In the specific disk shown in FIG. 3 there are 16 fiber-optic bodies 48.Rotation of disk 36 at such rate as to present approximately 20 viewsper second for each image (that is, for each value of n) produces a 3-Dsubstantially steady view of target subject 0. Accordingly, if each ofthe fiber-optic bodies on disk 36 corresponds to one discrete magnitudeof n, rotation of the disk at a speed of 20 revolutions per second willproduce an accurate 3-D image of target subject 0.

Because of the presence of synchronizing link 50 the speed of rotationof disk 36 is not critical. Moreover, the synchronization link permitsadaptation of the viewing device of FIG. 3 to reproducing, in 3-D form,information that has been stored on tape, film, or other storage media.

The relative lengths of the individual fiber-optic bodies 48 can beestablished in a nonlinear relationship to the Z planes to which therespective bodies correspond. The precise relationship can be used tomagnify selectively a given Z plane region of the target to avoid thedepth distortion alluded to above, or to achieve virtually any otherdepth alteration desired.

To effect further compensation for depth distortion, some of thefiber-optic bodies 48 can be formed so that the output faces (frontfaces) are sufficiently larger than the input faces (rear faces) thatthe images viewed from viewing station 44 through such bodies is largerthan the image formed on the input face of the body. Appropriate degreesof divergence of the fibers and appropriate lengths of fibers in thosebodies 48 that correspond to the rear or remote segments of the targetwill permit greater relative magnification of such remote images than ofthe images of the front or near segments of the subject. Thus distortionarising from the square law relationship between degree of magnificationand target range is remedied.

FIG. 4 shows a modification of the disk 36 of FIG. 3, the disk of FIG. 4being designated by 36. Supported on one face of the disk is a singlebody of optical fibers that is wedge-shaped in a peripheral orcircumferential sense so as to define a helical viewing face 56.Circular regions 57 are shown in FIG. 4 to indicate that disk 36' can beused interchangeably with disk 36; the circular regions are notstructurally different from the balance of the helical fiber-optic body,as a consequence of which a different number of images can be displayedon a device employing disk 36'. Although the structure of FIG. 4 issomewhat more difficult to fabricate than disk 36 in FIG. 3, thecontinuous surface 56 has the advantage of adapting the device todifferent values of n, that is, different numbers of depth increments ontarget subject 0 that are viewed. Such variation is achieved withoutstructural variation of the apparatus, needed variations being achievedby appropriate adjustments of pulser 24 and gate' generator circuit 22.

Still another modification is shown in FIG. 5. The disk 60 in FIG. 5 isformed of two transparent elements 62 and 64 that have different indicesof refraction. The two elements are shaped to define centrally of thedisk a helical interface 66. Thus at different circumferential locationsaround the disk, the image formed on one face of the disk will appearcloser to or farther from the viewer in accordance with the location ofthe interface with respect to the surface. Disk 60 has the advantagementioned hereinabove with respect to the device of FIG. 4, namely: thenumber of images formed about the periphery of the disk can be readilyvaried without mechanical adjustment of the apparatus.

FIG. 6 shows yet another modification of the viewing apparatus of theinvention. In FIG. 6, a screen, such as a frosted glass screen 70, issupported for movement toward and away from a viewing station 44 by anoscillating bar 71 that is moved in oscillatory motion toward and awayfrom the viewing station by an actuator 72. Lens 38 is carried by anauxiliary oscillating bar 71' that moves the lens in synchronism withscreen 70. One excursion of screen corresponds to one revolution of disk36 referred to above so that the sequence of images seen by the viewerof the apparatus of FIG. 6 is similar.

Another form of viewer is shown in FIG. 7. The optical input to theviewer is by way of a lens 73 in optical alignment with a mirror 74.Mirror 74 is mounted on a shaft 76 that is supported for rotation bybearings 78. The optical image is periodically gated to lens 73 andmirror 74 by interposition of an opto-electric image intensifier tube inthe optical path to lens 73. A motor 80 is provided for driving shaft 76through a suitable drive train 82. Spaced in a circle concentrically ofthe axis of shaft 76 is a frusto-conical reflector 84 which isconstructed and arranged to reflect an image from mirror 74 along alocus of parallel optical paths that reside in an imaginary cylinderconcentric with the axis of shaft 76. Axially spaced from reflector 84is a similar reflector 86 that is constructed and arranged to reflectthe image to a centrally located mirror 88 for display to an observer at90 through a lens 91. Reflector 88 is coupled to shaft 76 for rotationtherewith.

Spaced intermediate of reflectors 84 and 86 and within the abovementioned optical paths is a plurality of input faces 96 of pluralfiber-optics bodies 98. The fiber-optics bodies 98 have differentlengths in accordance with the description given hereinabove withrespect to FIG. 3 and specifically fiber-optics bodies 48. Accordingly,the image displayed to the viewer at 90 by reflector 88 will appear tomove toward and away from the viewer as shaft 76 is rotatably driven andas different images corresponding to images 30 in FIG. 2 are projectedonto input mirror 74. Appropriate synchronization signals applied toimage intensifier 75 achieve formation of appropriate images onrespective fiber-optics bodies 98 so as to provide a non-flickering 3-Dimage.

FIG. 8 depicts a 3-D viewing device that generates plural images in asingle plane. By providing apparatus that exploits stereopsis, or thecharacteristic of stereoscopic vision in humaneyes, an apparent 3-Dpresentation is afforded. Identical but separate images of a targetsubject are formed for the right and left eyes of the viewer, and suchimages are caused to move toward and away from one another in proportionto the range of the target subject. The viewer will observe the distancebetween the images, and plural images at different distances will beinterpreted by the brain of the viewer as a 3-D image.

The specific structure depicted in FIG. 8 is but one of the numeroustechniques for positioning the images in proportion to the range thatwill occur to those skilled in the art. In FIG. 8, a sequence of imagesis focused by lens system 38 from an image input such as a fiberopticbundle 32 onto an image splitter 100. The image 102 and 104 are spacedfrom one another by an amount appropriate for binocular viewing. Theimage intensifier tubes 102 and 104 are conventional devices that firstconvert photons to electrons at the input thereof, then accelerate theelectrons while preserving their respective spatial relation, andfinally reconvert the electrons to photons at the output so as toprovide a more intense image than appeared at the input. The electronswithin the tubes 102 and 104 are deflected laterally in accordance withthe present invention by opposed deflection coils 108a and 10812 inassociation with image intensifier 102 and by opposed deflection coils110a and 11012 in association with image intensifier 104.

The deflection coils are coupled to a programmable signal source 112which includes a feedback link 50' for operative connection with gategenerator 22. A variation of the apparatus of FIG. 8 is a device havingreflectors 100 and 106 mounted on individual galvanometer devices whichact to position the images in accordance with the magnitude of voltageapplied to the coils of the galvanometer. Such voltage, if madeproportional to range, will position the images at appropriate positionsin accordance with the range of the target subject.

The operation of the apparatus of FIG. 8 can be understood byconsidering the characteristic of the human eye known as stereopsis orstereoscopic vision. That is to say, duplicate images that arerelatively close to one another in a binocular viewing device willappear nearer to the viewer than duplicate images which are separatedfrom one another. The magnetic fields occurring across the deflectioncoil pairs, for example, deflection coils a and 110b, deflect theelectrons within image intensifier tube 104 by an amount correspondingto the strength and polarity of the field created by the coils. Gatecircuit 22 and signal source 112 are adapted to coact through link 50'to produce in the respective deflection coil pairs a field of strengthand polarity corresponding to the range of the particular target segmentdisplayed. Thus if the deflection coils 110a and 110b are energized soas to form an image on tube 104 that is toward image tube 102, and ifdeflection coils 108a and 108b are energized so as to form an image onimage tube 102 that is toward image tube 104, the viewer, when lookingat both image intensifier tubes and the images formed thereon, willperceive that the target subject is relatively close. On the other hand,if the images are formed on the sides of the image intensifier tubesremote from one another, the viewer will perceive the target subject asbeing relatively farther away. In accordance with established circuitrytechniques, the deflection control device 112 energizes coils 108a and108b 110a and 11% to achieve such positioning of the respective images,and the amount of deflection to which the images are subjectedcorresponds to the value of n in FIG. 2.

The specific target subject 0 shown in the drawings is a frustu'm of asolid cone; this exemplary target subject is used, not to limit theinvention, but merely as a convenient 3-D target to illustrate theoperation and features of the invention.

It will thus be seen that the present invention provides a system foracquiring and displaying 3-D information concerning a target subject.The display is in a real time domain so as to afford the viewer arealistic representation of the subject matter being viewed. Althoughthe system of FIG. 1 provides an immediate display of the target subject0, it will be obvious that the information can be stored, as on magnetictape or the like, and can be subsequently displayed. Thus recorder 20 isintended to exemplify apparatus that transmits images supplied theretoto display device 21 as well as memory or storage devices such as tapes,films, and the like. Moreover, the input to the display device generallyindicated at 21 in FIG. 1 can be either directly from a target, as shownin FIG. 1, from previously stored data, or from information derivedanalytically through a computer or drawn up according to available, dataor artistic concepts. Thus the system is useful in affording accuratevisualization of synthetic or hypothetical subjects as well as of realtarget subjects.

Although several embodiments of the invention have been shown anddescribed, it will be apparent that other adaptations and modificationscan be made without departing from the true spirit and scope of theinvention.

What is claimed is:

1. Apparatus for acquiring data that define the outline and range of atarget subject comprising a source of wave energy, means for formingpulses of the energy at plural range locations on the target subject sothat the plural range locations are sequentially illuminated by energyfrom said energy source to form outlines of each range zone, means forreceiving the energy pulses from the target subject, means forsequentially gating each of the energy pulses received so that asequence of outline images at discrete range distances is formed, andmeans for sequentially visually displaying the output of said gatingmeans, said displaying means including an optical system that producesimages corresponding to the image received by said receiving means, saiddisplaying means being adapted to produce images at a number of apparentdistances from the viewer that is equal to the number of discrete rangegate pulses and having an equal number of means that form imageproducing faces, the apparent distance of each particular imageproducing face corresponding to the range of the target zone representedby the particular image.

2. The invention of claim 4 wherein said displaying means comprises aviewing station, a circular disk having a face confronting said viewingstation, means for rotatively driving said disk about the central axisthereof, said axis being approximately normal to said face and beingspaced relative said viewing station such that an annular region of saiddisk face sweeps past said viewing station in response to rotation ofsaid disk, means for forming on the annular region of said disk face aplurality of optical imaging surface regions, each said surface regionbeing spaced from said viewing station by a different amount so thatimages on said surface regions that are in alignment with said viewingstation will appear at different distances, means in alignment with saidviewing station for producing on said surface regions a sequence ofimages of different range segments of the target body, and means forsynchronizing the rotation of said disk with said image producing meansso that the range segment of the target corresponds to the distance ofthe imaging surface portion at the instant that the surface portion isin alignment with the viewing station.

3. Apparatus according to claim 2 wherein said surface region forrningmeans comprises a plurality of fiber-optic bodies mounted on said diskabout the periphery thereof, said body having a front face adjacent saidviewing station and a rear face remote from said front face, said rearfaces being in mutually coplanar relationship and being adapted totransmit an image from said image forming device to the front facethereof to form an image on the front face, each said fiber-optic bodyhaving a length inversely proportional to the range distance of theimage produced on it by said image producing means.

4. Apparatus according to claim 2 wherein said sur face region formingmeans comprises a body of optical fibers disposed on said disk, saidbody having a plane rear annular face and a helical front annular faceopposite said viewing station.

5. Apparatus according to claim 2 wherein said surface region fomiingmeans comprises a body of optical fibers disposed on said disk, saidbody being formed by a plurality of arcuate segments the totality ofwhich form a generally annular body concentric with said disk, saidsegments having mutually coplanar rear faces, each said segment having afront face parallelly spaced from the rear face thereof by a differentdiscrete distance, whereby the front face of the surface region formingmeans is of generally arcuately stepped configuration.

6. Apparatus according to claim 2 wherein said surgffiriffileiil rfilrllfifiiff siiflilflf 883% having a front face and a rear face parallelto said front face, said annular body being formed by two segments oftransparent material that have different indices of refraction, eachsaid segment having a helical surface, said helical surfaces being inintimate contact to define a helical interface therebetween, saidinterface being intermediate said front and rear surfaces.

7. A viewing device having an objective lens that is arranged to beviewed along a path coterrninous with the optical axis thereof, a firstreflector disposed on said axis, means for rotating said first reflectorabout said axis so that a first circular path concentric with said axisis scanned as said first reflector is rotated, first reflecting meansdisposed in said first circular path for reflecting images from saidfirst reflector, second reflecting means spaced from said firstreflecting means for reflecting images impinging thereon from saidsecond reflecting means toward said axis, a second reflector disposed onsaid axis for establishing an optical path from said second reflectingmeans from an input disposed along the said axis, said second reflectorbeing coupled to said rotating means so that said first and secondreflectors rotate in unison, a plurality of fiber-optical bodiesdisposed intermediate said first and second reflecting means so that areflected image revolving between said first and second reflecting meansin response to rotation of said rotating means will sequentially passthrough said bodies, said bodies having different lengths and having theends thereof that are adjacent the said first reflecting means disposedin coplanar relationship so that the images reflected toward saidviewing device appear to be formed at different ranges, and means forsynchronizing the range of each image with the rotative position of saidfirst and second reflectors so that the range of an image is inverselyproportional to the length of a particular said fiber-optic body throughwhich each image is reflected.

1. Apparatus for acquiring data that define the outline and range of atarget subject comprising a source of wave energy, means for formingpulses of the energy at plural range locations on the target subject sothat the plural range locations are sequentially illuminated by energyfrom said energy source to form outlines of each range zone, means forreceiving the energy pulses from the target subject, means forsequentially gating each of the energy pulses received so that asequence of outline images at discrete range distances is formed, andmeans for sequentially visually displaying the output of said gatingmeans, said displaying means including an optical system that producesimages corresponding to the image received by said receiving means, saiddisplaying means being adapted to produce images at a number of apparentdistances from the viewer that is equal to the number of discrete rangegate pulses and having an equal number of means that form imageproducing faces, the apparent distance of each particular imageproducing face corresponding to the range of the target zone representedby the particular image.
 2. The invention of claim 4 wherein saiddisplaying means comprises a viewing station, a circular disk having aface confronting said viewing station, means for rotatively driving saiddisk about the central axis thereof, said axis being approximatelynormal to said face and being spaced relative said viewing station suchthat an annular region of said disk face sweeps past said viewingstation in response to rotation of said disk, means for forming on theannular region of said disk face a plurality of optical imaging surfaceregions, each said surface region being spaced from said viewing stationby a different amount so that images on said surface regions that are inalignment with said viewing station will appear at different distances,means in alignment with said viewing station for producing on saidsurface regions a sequence of images of different range segments of thetarget body, and means for synchronizing the rotation of said disk withsaid image producing means so that the range segment of the targetcorresponds to the distance of the imaging surface portion at theinstant that the surface portion is in alignment with the viewingstation.
 3. Apparatus according to claim 2 wherein said surface regionforming means comprises a plurality of fiber-optic bodies mounted onsaid disk about the periphery thereof, said body having a front faceadjacent said viewing station and a rear face remote from said frontface, said rear faces being in mutually coplanar relationship and beingadapted to transmit an image from said image forming device to the frontface thereof to form an image on the front face, each said fiber-opticbody having a length inversely proportional to the range distance of theimage produced on it by said image producing means.
 4. Apparatusaccording to claim 2 wherein said surface region forming means comprisesa body of optical fibers disposed on said disk, said body having a planerear annular face and a helical front annular face opposite said viewingstation.
 5. Apparatus according to claim 2 wherein said surface regionforming means compRises a body of optical fibers disposed on said disk,said body being formed by a plurality of arcuate segments the totalityof which form a generally annular body concentric with said disk, saidsegments having mutually coplanar rear faces, each said segment having afront face parallelly spaced from the rear face thereof by a differentdiscrete distance, whereby the front face of the surface region formingmeans is of generally arcuately stepped configuration.
 6. Apparatusaccording to claim 2 wherein said surface region forming means comprisesan annular body of transparent material secured to said disk, said bodyhaving a front face and a rear face parallel to said front face, saidannular body being formed by two segments of transparent material thathave different indices of refraction, each said segment having a helicalsurface, said helical surfaces being in intimate contact to define ahelical interface therebetween, said interface being intermediate saidfront and rear surfaces.
 7. A viewing device having an objective lensthat is arranged to be viewed along a path coterminous with the opticalaxis thereof, a first reflector disposed on said axis, means forrotating said first reflector about said axis so that a first circularpath concentric with said axis is scanned as said first reflector isrotated, first reflecting means disposed in said first circular path forreflecting images from said first reflector, second reflecting meansspaced from said first reflecting means for reflecting images impingingthereon from said second reflecting means toward said axis, a secondreflector disposed on said axis for establishing an optical path fromsaid second reflecting means from an input disposed along the said axis,said second reflector being coupled to said rotating means so that saidfirst and second reflectors rotate in unison, a plurality offiber-optical bodies disposed intermediate said first and secondreflecting means so that a reflected image revolving between said firstand second reflecting means in response to rotation of said rotatingmeans will sequentially pass through said bodies, said bodies havingdifferent lengths and having the ends thereof that are adjacent the saidfirst reflecting means disposed in coplanar relationship so that theimages reflected toward said viewing device appear to be formed atdifferent ranges, and means for synchronizing the range of each imagewith the rotative position of said first and second reflectors so thatthe range of an image is inversely proportional to the length of aparticular said fiber-optic body through which each image is reflected.